The present invention concerns a new method of forming steroidal-17yl-propiolactones.
It is known that .DELTA..sup.4 -3-ketosteroid-17-propiolactones, for example, 3-(17.beta.-hydroxy-4-androsten-3-one-17.alpha.-yl)propionic acid lactone, can be produced by homogeneous hydrogenation of the corresponding 17.alpha.-hydroxypropynyl-.DELTA..sup.4 -3-keto steroids to obtain the corresponding 17.alpha.-hydroxypropyltestosterones, and subsequent Jones oxidation in a two-stage reaction (U.S. Pat. No. 4,129,564).
Hydrogenation with homogeneous catalysts, e.g. tris(triphenyl)phosphine rhodium chloride, in addition to high catalyst cost, has the disadvantage that rhodium, objectionable from a toxicological viewpoint anyway, can be removed from the subsequent stages only with great expenditure.